Electrical connector assembly



United States Patent '"ice US. Cl. 20050 2 Claims ABSTRACT OF THE DISCLOSURE The disclosure relates toan electrical connector assembly having first and second connector elements, which when connected to each other, establish one or more electrical circuits. A left-hand thread is provided on one of the connector elements and a right-hand thread on the other with a coupling nut for coupling the, connector elements together. The dimensions of the nut are such that mating of the contacts occurs in a totally closed space. Further, the first connector element contains sealed magnetically operable reed contacts in the circuit leading to the contacts of the element. The contacts are normally open and after the two connector elements have been engaged by the nut, a magnet is moved into a position wherein the reed contacts are closed. The contacts of the elements can only mate and unmate when the reed contacts are open. The magnet may be mounted on a bracket hinged on the second connector element, the bracket including means which, when the reed contacts are closed, prevents rotation of the nut.

The invention relates to an electrical connector assembly with first and second connector elements connectable to each other to establish one or more electrical circuits.

In a dangerous atmosphere, such as one including petrol fumes, a spark such as often happens when conventional connectors are disconnected could cause an explosion, if the connector parts are mated or unmated to complete or interrupt live electrical circuits.

The general object of the invention is to realize an explosion proof connector of a particularly simple and effective nature.

In accordance with-a first feature of the invention, an electrical connector assembly as initially defined is characterized in this, that it includes outer'casingsfor said connector elements, a left-hand thread on the casing of one of said elements and a right-hand thread on the casing of the other of said elements, and a coupling nut for coupling said connector elements together, wherein said coupling nut has a left-hand screw thread at one of its ends and a right-hand screw thread at the other of its ends, wherein rotation of said nut when its screw threads mate with those of said connector elements can draw the elements together to cause the contacts carried by said elements to mate, and wherein the dimensions of said nut are such that the mating and unmating of said contacts always occur in a totally enclosed space.

In accordance with a second feature of the invention, said first connector element carries sealed magneticallyoperable contacts, e.g. reed contacts, included in the circuits leading to the contacts of that element, which sealed contacts are normally open, wherein said second connector element carries a magnet which is movable between a first position in which it is not in operative relation with said sealed'contacts which arethen open and a second position in which it is in operative relation with said sealed contacts which are then closed, and wherein 3,475,569 Patented Oct. 28, 1969 said elements can only mate and unmate when said sealed contacts are open.

Thus, double safety is provided since in addition to interrupting the electrical connections to one of the connector elements before closing or opening the connector contacts the latter operations can only take place in a confined space. If gas is present therein and, assuming failure of the magnetic safety action, is ignited by a spark jumping between pin and socket terminals, all that is required is that the connector be mechanically strong enough to withstand the explosion. Precision machining of the threads for the coupling nut arrangement will insure that the ignited gases will be cooled oil? through the threads before reaching the outside atmosphere, so that no outside gases may be ignited.

The above and other objects and features of the in vention will become more apparent and the invention itself will be best understood by referring to the following description of embodiments taken in conjunction with the accompanying drawings which represent:

FIG. 1, a top plan view of a connector assembly, in accordance with the invention, with its magnet clamp in position;

FIG. 2, a sectional view of the assembly of FIG. 1 taken at right angles to FIG. 1;

FIG. 3, a top plan view of a slightly modified version of the connector assembly;

FIG. 4, a section of part of the assembly of FIG. 3, but shown inverted as compared with the corresponding view of FIG. 2 and;

FIG. 5, an exploded view of the reed housing and magnet support for the connector of FIGS. 3 and 4;

FIG. '6, an exploded view of the remaining part of the free element on top of the captive element for the connector of FIGS. 3 and 4; and

FIG. 7, an exploded view of the captive element shown in FIG. 6.

The connector assemblies described herein each include a first and a second connector element, each connected to one of the sets of wires to be interconnected.

The first connector element carries a pivoted clamp bracket bearing a permanent magnet or two permanent magnets, while the second element, which has an obtuse angle between its ends has a set of sealed reed contact units. These contacts are made of a magnetically and electrically conductive metal and each sealed contact unit consists of a glass (or plastics) tube with two reeds sealed into it, one at each end. These reeds have their ends overlapping, but are so pre-tensioned as to .nor mally be open. Their contacts are each included in the circuit between one of the wires where it enters the second connector element and the elements connector proper.

To unite the connector elements, the elements are brought together so that the plug and socket portions engage, which latter occurs inside a coupling nut. This has two opposite threads each engaging one of the connector elements so that rotating the nut in one sense draws the elements together. Rotation in the other sense urges the elements apart. Thus the plugs and sockets make or break in an enclosed space. After the engagement has been effected, the clamp with the magnet(s) is swung into its operative position, which closes the reed contacts to complete the circuits through the wires of the elements. When the clamp is in position, a securing screw is adjusted to clip the clamp to the first connector element. In this condition the coupling nut cannot disengage the plugs/ sockets.

To increase the margin of safety still further the magnet could be an electro-magnet which is only energised to close the reed contacts after the connector elements have been fitted to ether into their final position. Then the electro-magnet can be energised either manually or automatically.

Turning now to the arrangement shown in FIGS. 1 and 2, the coupling nut is shown at 1, and as shown in FIG. 1 part of its surface is knurled for convenience of operation. This nut has on its inside two oppositely-handed screw threads one of which engages a portion 2 of the captive connector element while the other thread engages a portion 3 of the free connector element. Within these portions there are inserts 4 and 5 which contain the contact elements proper. This portion of the assembly is fairly conventional and will not therefore be described in great detail.

The free element of the assembly has a tag board 6 including a printed circuit if required, carrying a set of reed contact units 7, protected by a sponge pad 8. These contact units, as can be seen from FIG. 2 are connected between the wires of the cable 9 and the connector units in the insert 5.

The captive element has a U-shaped bracket 10 on which is pivotally mounted a clamp bracket 11, which has two legs each pinned to one of the legs of the bracket 10 and interconnected by a stitfening bar 12. The bracket 11 has a rectangular end portion 13 within which is mounted a permanent magnet 14 or two similar parallel magnets.

When the connector is in the operative condition as shown in FIG. 2, a screw 16 located in a hole 38 in the cover of the free element of the connector. This hole 38 can also be used to pour a potting compound such as a mineral-filled epoxy into the reed switch cam wiring cavity of the free element to fill that cavity. Similarly, potting compound can be introduced into bore 39 of the fixed element after wiring.

To connect the elements, the nut 1 is rotated in its normal anti-clockwise undoing since, until a stop pin 15 abuts a shoulder 35 on the free element, the end of which is then within the end of the nut. The two elements are then offered up, i.e. brought together, and the coupling rotated clockwise to engage the nuts thread on the fixed element 2. To ensure that the connector elements are correctly orientated before the thread engagement occurs, fliere is a polarising pin 36 on the free element. This engages the outer end of a hole 37 in the fixed element. The contacts in the inserts 4 and 5 are then brought into engagement and urged together by the nut 1. When they are properly engaged, the bracket 11 is swung from its normal position to the position shown in FIG. 2, so that the circuits from the cable 9 to the plug/socket units are completed as a result of the closure of the reed contacts by the magnet. The side arms of the bracket 11 are so shaped adjacent to the stilfener 12 as to give working clearance to the flats 40 on the coupling nut. There it is mechanically impossible to rotate the coupling nut with the bracket in the operative position shown in FIG. 2. Likewise, the shape of the elements is such as to prevent the displacement of the bracket 11 to the fully operative position closing contacts 7 unless the connector is fully mated and the coupling nut 1 tightened.

To disengage the elements, the screw 16 is loosened so that the bracket 11 can swing out. The nut 1 can now be rotated to disengage the plug/socket elements.

It will thus be seen that the connector is always dead electrically when the contacts in the grommets 4 and 5 disengage.

The two elements in the assembly of FIGS. 1 and 2 are at 135 to each other. It would be possible however, for them to be at any required angle. If aligned the shape of the magnet-carrier is slightly simplified and a lip at the end of the magnet-carrier is provided to fit over a raised portion which houses the reeds.

In the device of FIGS. 3, 4, 5 and 6, the captive element (FIG. 7) includes an adaptor 20, a bracket 21 for carrying the magnet bracket, a cir-clip 22, and a shell unit 23, which is the connector proper. This has socket contact units, as shown. These four parts fit together as indicated at 24 to form the captive connector element.

The free element has a barrel portion 25 (FIG. 6), with the plug connector portion shown at 26 and a cable clamp 27 and nut 28. The reeds and their housing (FIG. 5) include an insulator 29, a reed panel 30 and a cover 31 to be fixed to the barrel portion 25. The insulator 29 fits within the cover 31, which also includes a sponge pad 33. The construction of the magnet support 32 hinged on bracket 21 is also shown on FIG. 5, the magnet 34 being a circular magnet.

While the principles of the invention have been described above in connection with specific apparatus, it is to be clearly understood that this description is made only by way of example and not as a limitation on the scope of the invention.

I claim:

1. An electrical connector assembly with first and second connector elements connectable to each other to establish one or more electrical circuits, comprising outer casings for said connector elements, a left-handed thread on the casing of one of said elements and a right-hand thread on the casing of the other of said elements, and a coupling nut for coupling said connector elements together, wherein said coupling nut has a left-hand screw thread at one of its ends and a right-hand screw thread at the other of its ends, wherein rotation of said nut when its screw threads mate with those of said connector elements can draw the elements together to cause the contacts carried by said elements to mate, and wherein the dimensions of said nut are such that the mating and unmating of said contacts always occur in a totally enclosed space; said first connector element containing sealed magnetically-operable reed contacts, included in the circuits leading to the contacts of that element, said sealed contacts being normally open, wherein said second connector element carries a magnet which is movable be tween a first position in which it is not in operative relation with said sealed contacts which are then open and a second position in which it is in operative relationwith said sealed contacts which are then closed, and wherein the screw threads on said nut can only be engaged with the screw threads on said connector elements when said magnet is in said first position, so that the contacts of said elements can only mate and unmate when said sealed contacts are open; said first and second connector elements making an obtuse angle with one another, said magnet being mounted on a bracket hinged on said second' connector element so as to be swung into said second position outside said angle.

2. An electrical connector assembly with first and second connector elements connectable to each other to establish one or more electrical circuits, comprising outer casings for said connector elements, a left-hand thread on the casing of one of said elements and a right-hand thread on the casing of the other of said elements, and a coupling nut for coupling said connector elements together, wherein said coupling nut has a left-hand screw thread at one of its ends and a right-hand screw thread at the other of its ends, wherein rotation of said nut when its screw threads mate with those of said connector elements can draw the elements together to cause the contacts carried by said elements to mate, and wherein the dimensions of said nut are such that the mating and unmating of said contacts always occur in a totally enclosed space; said first connector element containing sealed magnetically-operable reed contacts, included in the circuits leading to the contacts of that element, said sealed contacts being normally open, wherein said second connector element carries a magnet which is movable between a first position in which it is not in operative relation with 5 6 said sealed contacts which are then open and a second References Cited position in which it is in operative relation with said sealed UNITED STATES PATENTS contacts which are then closed, and wherein the screw 2,848,572 8/1959 wagnecz threads on said nut can only be engaged with the screw 3,104,144 9/1963 spmle.

threads on said connector elements when said magnet is 5 3 271 725 9 19 Bloch in said first position, so that the contacts of said elements can only mate and unmate when said sealed contacts are ROBERT SCHAEFER, Primary Examiner open; said magnet being mounted on a bracket hinged on D. SMITH JR., Assistant Examiner said second connector element, said bracket including a 10 part which, when in said second position, prevents the US rotation of said nut. ZOO-51.09; 339111 

